Capacity can be increased by exploiting the space dimension inherent to any wireless communication system. Recent information theoretic results show that simultaneous use of multiple receive and multiple transmit antennas can offer dramatic increase in capacity. In this paper each cell-site receiver and each user terminal is assumed to be equipped with multiple antennas. Then,under a per transmit antenna power constraint, a closed form expression for the optimum capacity is found using the well known Wyner's model. The results show that even one antenna per-user is enough to achieve the limit and offer an insight in the behavior of the capacity for a Gaussian cellular Multiple-access Channel (GCMAC) with MIMO in different fading environments.